Mail bomber kills again in 16 year spree

A senior advertising executive decapitated by a bomb sent through the mail which exploded as he opened it in his kitchen in New Jersey is the latest victim of a serial bomber who has struck 15 times since 1978.

Thomas J Mosser, 50, was killed instantly by a bomb the size of a video tape. The FBI say the meticulously constructed device is similar to that used in attacks which have now killed two people and wounded 23 but have no known motive.

Federal investigators know very little about the bomber who appears to pick his victims at random though in the past he appears to have had a grudge against universities and airlines. Briefly sighted in 1987 as he placed a bomb behind computer store, he is said to be a white male with a ruddy complexion and red or blond hair. He has often engraved the initials "FC" on his bombs.

Dubbed "Unabom" by federal investigators, who are offering a $1m reward for information which will secure his conviction, he appears to carry out the attacks in part as a demonstration of his technical expertise rather than because of any particular animus against his victims. Mr Mosser may have been chosen simply because his name appeared in the New York Times on 5 December when he was promoted to be general manager of Young & Rubicam, one of the world's largest advertising firms.

The bombs are very carefully constructed with parts - even those available in hardware stores - made and polished at home. This makes it difficult to trace them, though the packages containing the bombs are mailed from northern California. Starting in 1978, the first to be attacked were airline executives, but recent victims have been academics, two professors, one in Califronia and one in New Haven, receiving bombs last year.

The only small piece of evidence about the motive for attacks is a letter sent to the New York Times last year from Sacramento, California saying the author belonged to ``an anarchist group calling ourselves FC". It promised to "give information about our goals at some future time." No other information was received.